23 research outputs found

    Producing Fiber Reinforced Composites Having Dense Ceramic Matrices

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    A fiber preform is partially infiltrated with a ceramic material. A porous solid polymer is formed by reaction forming the infiltrated preform which is then pyrolized. Microporous carbon in the composite matrix is converted into silicon carbide

    Opportunities for genetic improvement of lamb survival

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    Data on lamb survival and associated traits involving records from 15 192 lambs, 6308 dams and 284 sires from the Sheep CRC's Information Nucleus were studied. Lamb survival to 3 days of age and to weaning was 85 and 80%, respectively, and heritability (±s.e.) was 0.014 ± 0.010 and 0.010 ± 0.010, respectively. Of the 14 traits recorded at birth, time taken for the lamb to bleat, rectal temperature and crown–rump length had the highest genetic correlations with lamb survival to weaning (–0.43 ± 0.32, 0.56 ± 0.33 and –0.38 ± 0.36, respectively). Under selection for a multi-trait objective including net reproduction rate (but not lamb survival), survival was predicted to decline genetically by 0.25 lambs weaned per 100 lambs born.year, although this was reversed to a gain of 0.20 lambs weaned per 100 lambs born.year by including the trait in the breeding objective and using 50 half-sib and 50 progeny records per selection candidate. Accuracy of selection for lamb survival was improved to 0.735 with a selection index of lamb survival to weaning, lamb ease, birth coat score, time taken to bleat, rectal temperature and crown–rump length, with the addition of 50 half-sibs and 50 progeny records per candidate. Our results suggest that unless actively incorporated into breeding objectives, lamb survival may genetically decline; however, gains are possible with direct selection using half-sib and progeny records. The addition of indirect selection criteria for lamb survival can further improve accuracy, up to 93.4%, but requires further investigation

    Data in Antarctic science and politics

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    The internationalization of Antarctica as a continent for science with the Antarctic Treaty (1961) was heralded as bringing about international cooperation and the free exchange of data. However, both national rivalry and proprietorship of data, in varying degrees, remained integral to Antarctic science and politics throughout the 20th century. This paper considers two large field-surveys in Antarctica: first, an aerial photographic survey carried out by the Ronne Antarctic Research Expedition of 1946—8; and second, the Scott Polar Research Institute's radio-echo sounding survey of 1967—79. Both surveys involved geoscientific data but the context in which the investigations and the exchanges of their results took place changed. We argue that the issue of control of data remained paramount across both cases despite shifting international political contexts. The control of data on Antarctic territory, once framed in terms of geopolitics and negotiated between governments, became a matter of science policy and credit to be negotiated among scientific institutions. Whereas the Ronne data were of potential strategic value for reinforcing national territorial claims, the radio-echo sounding data contained information of potential economic and environmental value
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